DS4G ion engine

The dual-stage 4-grid (DS4G) thruster is a new design for a highly efficient ion engine designed and built at the Australian
National University and sold to the European Space Agency (ESA) which laid
down some basic conceptual requirements. According to the results of tests,
announced in January 2006, DS4G achieved an exhaust
velocity of 210 kilometers per second – more than 10 times faster
than possible with the ion engines used on Deep Space
1 and SMART-1, and four times faster
than the latest prototype ion engine designs.

How it
works

Traditional ion engines use three closely separated perforated grids containing
thousands of millimeter-sized holes attached to a chamber containing a reservoir
of charged particles. These systems effectively extract and accelerate the
ions in one stage, which because of physical constraints limits the extraction
potential applied between the first and second grids to 5 000 V. The DS4G
ion engine solves this limitation by effectively decoupling the acceleration
from the extraction process into a two-stage system. This allows for independent
throttling of the exhaust velocity but more importantly allows very high
accelerating fields to be applied to the second stage without adversely
affecting the extraction field. The test model has reached total acceleration
potentials as high as 30,000 V, resulting in the high exhaust velocity noted
above.

Future missions using DS4G engines

"Using a similar amount of propellant as SMART-1, a future spacecraft using
our new engine design wouldn't just reach the Moon, it would be able to
leave the Solar System entirely," according to an ESA press release. Once
developed into full flight ready devices, these engines will propel spacecraft
to the outermost planets, the newly discovered planetoids beyond Pluto and further into interstellar space, all with-in the working lifetime of
a mission scientist.

Closer to home, these supercharged ion engines could figure prominently
in the human exploration of space. With an adequate supply of electrical
power, a small cluster of larger, high power versions of the new engine
design would provide enough thrust to propel a crewed spacecraft to Mars and back.